scholarly journals Analyticity of the scattering amplitude, causality, and high-energy bounds in quantum field theory on noncommutative space–time

2006 ◽  
Vol 47 (9) ◽  
pp. 092302 ◽  
Author(s):  
Anca Tureanu
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Scattering Amplitude ◽  
High Energy ◽  
Space Time ◽  
Noncommutative Space ◽  
Quantum Field ◽  
Energy Bounds

scholarly journals HIGH ENERGY SCATTERING IN THE QUASIPOTENTIAL APPROACH

2012 ◽  
Vol 27 (01) ◽  
pp. 1250004 ◽  
Author(s):  
SUAN HAN NGUYEN ◽  
THI HAI YEN LE ◽  
NHU XUAN NGUYEN
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Asymptotic Behavior ◽  
Scattering Amplitude ◽  
High Energy ◽  
Quantum Field ◽  
Quasipotential Approach ◽  
Scalar Particles ◽  
Systematic Scheme ◽  
High Energy Scattering

Asymptotic behavior of the scattering amplitude for two scalar particles by scalar, vector and tensor exchanges at high energy and fixed momentum transfers is reconsidered in quantum field theory. In the framework of the quasipotential approach and the modified perturbation theory a systematic scheme of finding the leading eikonal scattering amplitudes and its corrections are developed and constructed. The connection between the solutions obtained by quasipotential and functional approaches is also discussed. The first correction to leading eikonal amplitude is found.

QUANTUM FIELD THEORY ON NONCOMMUTATIVE SPACE–TIME: THE RELATION BETWEEN ULTRAVIOLET BEHAVIOUR, TOPOLOGY AND SYMMETRY

2001 ◽  
Vol 16 (04n06) ◽  
pp. 235-240
Author(s):  
M. CHAICHIAN ◽  
A. DEMICHEV ◽  
P. PREŠNAJDER
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Star Product ◽  
Space Time ◽  
Time Variable ◽  
Noncommutative Space ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Interaction Terms ◽  
Scalar Quantum

We study properties of a scalar quantum field theory on two-dimensional noncommutative space–times. We show that ultraviolet behaviour of a field theory on noncommutative spaces is sensitive to the topology of the space–time, namely to its compactness. The compactness of space-like coordinates implies discreteness of the time variable which leads to appearance of unphysical modes and violation of unitarity even in the absence of a star-product in the interaction terms. Thus, this conclusion holds also for other quantum field theories with discrete time.

scholarly journals ε-EXPANSION IN QUANTUM FIELD THEORY IN CURVED SPACE–TIME

1998 ◽  
Vol 13 (16) ◽  
pp. 2857-2874
Author(s):  
IVER H. BREVIK ◽  
HERNÁN OCAMPO ◽  
SERGEI ODINTSOV
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Space Time ◽  
Quantum Field ◽  
Curved Space ◽  
Njl Model ◽  
Effective Lagrangian ◽  
Special Solutions ◽  
Curvature Approximation ◽  
Symmetric Phase

We discuss ε-expansion in curved space–time for asymptotically free and asymptotically nonfree theories. The existence of stable and unstable fixed points is investigated for fϕ4 theory and SU(2) gauge theory. It is shown that ε-expansion maybe compatible with aysmptotic freedom on special solutions of the RG equations in a special ase (supersymmetric theory). Using ε-expansion RG technique, the effective Lagrangian for covariantly constant gauge SU(2) field and effective potential for gauged NJL model are found in (4-ε)-dimensional curved space (in linear curvature approximation). The curvature-induced phase transitions from symmetric phase to asymmetric phase (chromomagnetic vacuum and chiral symmetry broken phase, respectively) are discussed for the above two models.

scholarly journals COMPUTER PROGRAMS FOR ANALYTICAL PERTURBATIVE CALCULATIONS IN HIGH ENERGY PHYSICS

1994 ◽  
Vol 05 (06) ◽  
pp. 1089-1101 ◽  
Author(s):  
LEVAN R. SURGULADZE
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
High Energy Physics ◽  
Short Review ◽  
High Energy ◽  
Quantum Field ◽  
Perturbative Calculations ◽  
Mathematical Algorithm ◽  
Recent Computer ◽  
Energy Physics

A short review of the present status of computer packages for the high order analytical perturbative calculations is presented. The mathematical algorithm and the quantum field theory methods used are briefly discussed. The most recent computer package HEPLoops for analytical computations in high energy physics up to four-loops is also discussed.

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